842 



" P. Phegopteris." A Polypodium, W. J. H. 



" P, Oreopteris." A Lastrcea, W. J. H. 

 " § III. Leaves winged ; wings deeply wing-cleft. 



" P. Filix-mas." A Lastrma P W. J. H. 



" P. Thelypteris." A Lastraa, W. J. H. 



" P. dentatum." A Cystopteris, W. J. H. 



" P. fontanum.'' An Asplenium, W. J. H. 

 " § IV. Leaves doubly winged. 



" P. aculeatum." A Polystichum, W. J. H. 



" P. spinulosura." A Lastrma, W. J. H. 



" P. Filix-foemina." An Athyrium, W. J. H. 



" P. cristatum." A Lastraa, W. J. H. 



" P. fragile." A Cystopteris, W. J. H. 



« P. trifidum." A Woodsia P W. J. H. 



" P. rhoeticum." An Athyrium, W. J. H. 

 " § V. Leaf triply winged. 



" P. Dryopteris." A Polypodium, W, J. H. 



We could analyze many of Sir William Hooker's divisions with a 

 similar result, particularly his genus Hymenophyllum, which is made 

 to comprise a family of ferns separable into generic divisions by cha- 

 racters of surpassing distinctness derived from the fructification. Sir 

 William divides this group precisely on the same plan as that adopted 

 above by Withering in Polypodium, the result is of course the same, 

 that of dissevering allied species, or even varieties of the same spe- 

 cies, and of associating species that have no characters in common, 

 except the mode in which the frond happens to be divided, a charac- 

 ter we might describe as being totally unavailabe. 



It would appear from the author's own statement that when he 

 wrote this part of the work he was unaware of Presl's admirable 

 Monograph of the family; for in Part II., which appeared in 1844, 

 this monograph is not mentioned, although it had been nearly two 

 years before the public, and therefore this want of knowledge seems 

 unaccountable and inexcusable: however, immediately after the pub- 

 lication of Part II. of the * Species Filicum,' a complete analysis of 

 Presl's work appeared in the pages of the * Phytologist ;' then, the 

 Hymenophyllaceae being still unfinished, it became necessary to no- 

 tice Presl's labours, which is accordingly done in Part III, and a 

 Synopsis is given, preceded by the remark we have already quoted as 

 objecting to generic characters being derived from the fructification. 

 To those who are not pteridologists any comments on the labours of 

 these two authors would be unintelligible, to those who are pterido- 

 logists we would suggest a comparison of the two systems. 



